U.S. patent application number 12/951193 was filed with the patent office on 2011-07-14 for sacrificial catalyst polycrystalline diamond element.
This patent application is currently assigned to National Oilwell DHT, L.P.. Invention is credited to Alan Honggen Jiang, Harold Sreshta.
Application Number | 20110171414 12/951193 |
Document ID | / |
Family ID | 45217691 |
Filed Date | 2011-07-14 |
United States Patent
Application |
20110171414 |
Kind Code |
A1 |
Sreshta; Harold ; et
al. |
July 14, 2011 |
Sacrificial Catalyst Polycrystalline Diamond Element
Abstract
A superhard composite material comprising a polycrystalline
diamond cutter (PDC) having a cutting surface and cutting edges
having a polycrystalline diamond thickness of about 3 mm is
integrally formed with a sacrificial catalyst source that is
removed later in the processing of the of the cutter.
Inventors: |
Sreshta; Harold; (Houston,
TX) ; Jiang; Alan Honggen; (Gloucester, GB) |
Assignee: |
National Oilwell DHT, L.P.
|
Family ID: |
45217691 |
Appl. No.: |
12/951193 |
Filed: |
November 22, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61294897 |
Jan 14, 2010 |
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Current U.S.
Class: |
428/64.1 ;
428/141; 428/192; 428/323; 428/328; 428/332; 428/76; 428/80;
51/307; 51/309 |
Current CPC
Class: |
E21B 10/00 20130101;
Y10T 428/24355 20150115; Y10T 428/26 20150115; Y10T 428/24777
20150115; E21B 10/5673 20130101; Y10T 428/239 20150115; C22C
2204/00 20130101; B22F 7/06 20130101; Y10T 428/25 20150115; Y10T
428/256 20150115; B22F 2005/001 20130101; C22C 26/00 20130101; B22F
3/26 20130101; C22C 2026/001 20130101; Y10T 428/21 20150115; E21B
10/573 20130101 |
Class at
Publication: |
428/64.1 ;
428/332; 428/76; 428/192; 428/323; 428/328; 51/307; 51/309;
428/141; 428/80 |
International
Class: |
B24D 3/04 20060101
B24D003/04; B24D 3/10 20060101 B24D003/10; E21B 10/46 20060101
E21B010/46 |
Claims
1. A superhard composite material comprising a polycrystalline
diamond cutting element comprising a cutting surface with a
finished polycrystalline diamond thickness of between about 2 mm
and about 5 mm and comprising a high-temperature, high-pressure
in-situ formed cemented carbide substrate that is integrally bonded
to the PCD.
2. The superhard composite material of claim 1 further comprising a
can and a lid for the HTHP component assembly with a shrink factor
of about 1.10 for minimal OD grinding, and the thickness of the
in-situ formed cemented carbide substrate is between about 6 and 20
mm.
3. The superhard composite material of claim 1 wherein a cobalt
catalyst for Diamond-Diamond particle sintering and WC-WC
cementation is supplied by a sacrificial cemented carbide substrate
with an average grain size of 20 .mu.m and cobalt of 35 wt %.
4. The superhard composite material of claim 3 wherein the finished
cutter is about 1613 mm in diameter.
5. The superhard composite material of claim 3 wherein the
sacrificial substrate in contact with the diamond particle forms a
conic bevel at an outside diameter to form an in-situ chamfer on
the PCD after HTHP processing.
6. The superhard composite material of claim 5 wherein the diamond
feed stock is a mono modal size of about 50.mu..
7. The superhard composite material of claim 5 wherein the WC
particle size in contact with the diamond particle is a mono modal
size of about 50 .mu.m.
8. The superhard composite material of claim 5 wherein a transition
Diamond--WC layer is formed by using a probing tool that is used to
selectively transfer WC particle into the diamond particle bed to a
depth of about 1 mm.
9. The superhard composite material of claim 2 wherein the can and
lid mechanically sealed.
10. The superhard composite material of claim 2, wherein the can is
exposed to a HTHP process to enable composite densification aided
via a catalyst infiltration from the cemented carbide substrate
into the diamond and WC particle bed, wherein the cemented carbide
substrate is a sacrificial substrate, and wherein the HTHP
processing is at least 40 kbar pressures and the temperature is at
least 1000.degree. C.
11. The superhard composite material of claim 2, wherein the sweep
or movement of the catalyst during HTHP processing occurs from the
top of the PCD surface to the bottom of the in-situ formed
substrate.
12. The superhard composite material of claim 11 wherein after HTHP
processing, the super hard composite is finished by removal of the
can/sacrificial substrate and OD grinding.
13. The superhard composite material of claim 11 wherein the
sacrificial substrate is formed of a metal carbide selected from
the group consisting of a tungsten carbide, titanium carbide,
tantalum carbide, and mixtures thereof.
14. The superhard composite material of claim 13 wherein the
sacrificial substrate is formed of a carbide from the group of IVB,
VB, or VIB metals which is pressed and sintered in the presence of
a binder of cobalt, nickel, iron, and alloys thereof, and further
comprises: an average carbide particle size greater than >3
.mu.m, a weight % Binder >3, a binder comprising Co, Ni, or Fe
with at least 5 wt % Co in the sacrificial binder phase.
15. The superhard composite material of claim 14 wherein WC is
replaced with MC comprising M=V, Mo, Ti, Ta) and mixes thereof with
a WC content of at least 5 wt %.
16. The superhard composite of claim 15 wherein the sacrificial
binder substrate that has M, C, Co (Fe, Ni) a eutectic composition
forming 100% melt at the eutectic temperature; W, C, Co--Ni
eutectic temperate is about 1270 degrees C.
17. The superhard composite material of claim 1 wherein a surface
texture of the sacrificial substrate in contact with the diamond
particle comprises: a surface texture on the substrate is the
negative of the desired roughness on the cutting element face, and
the texture is formed by pressing the grade mix or post sintered
operations including laser, EDM or other methods for providing the
texture.
18. The superhard composite material of claim 17 wherein the
texture can have chip breaker geometries used for milling and
turning inserts to aid with chipping of formation.
19. The superhard composite of claim 1 wherein the Diamond
particles have a multi-modal size distribution for optimal packing
with a size range of 1 nm to 100 .mu.m, and the diamond particles
have a carbon phase additive >5 wt % that is amorphous or nano
structure fullerenes.
20. The superhard composite of claim 19 wherein the diamond
particles are replaced with CBN particles.
21. The superhard composite of claim 20 further comprising a
mixture of Diamond and CBN particles comprising at least 0.5 wt %
diamond particles.
22. The superhard composite of claim 1 wherein the interface
probing depth may be 100% of the PCD layer with a low WC
concentration near a sacrificial substrate and a high concentration
near the WC-diamond interface.
23. The superhard composite of claim 1 wherein the WC content in
diamond particle bed ranges at the preformed interface ranges from
1 wt % to 80 wt %.
24. The superhard composite of claim 1 wherein the Carbide
particles are formed of a metal carbide selected from the group
consisting of tungsten carbide, titanium carbide, tantalum carbide,
and mixtures thereof from the group of IVB, VB, or VIB metals, and
comprising a multi modal particle size distribution for optimal
packing with a size range of 1 nm to 100 .mu.m, wherein at least 5
wt % of the particles are >50 .mu.m to ensure adequate erosion
resistance of the HTHP in-situ formed substrate.
25. The superhard composite of claim 1 wherein the diamond
particles, interface and WC particle bed are preforms manufactured
using a fugitive binder like PEG, mineral oil and methyl cellulose
to limit segregation during transfer to the can, wherein, a
moldable diamond mix is pressed in the can to conform to the
sacrificial substrate texture, an interface is formed by using a
probing tool to transfer a given amount of WC mix into the diamond
mix, a WC mix is pressed into the can above the interface, and the
fugitive binder is removed in the presence of hydrogen.
26. The superhard composite of claim 1 comprising a sink for a
catalyst abridging the WC bed to reduce catalyst content in the
densified PCD/substrate wherein the sink comprises loose Zirconia
ceramic particles and the like, that have greater resistance to
HTHP sintering than WC particles in the presence of said catalyst,
and wherein the sink is removed after HTHP processing via a EDM,
laser or abrasive cutting.
27. The superhard composite of claim 1 wherein substrate removal is
by a mechanical dry/wet abrasives grinding or chemical leaching or
a combination of both methods.
28. The superhard composite of claim 1 wherein the PCD face is
coated with a nano coating diamond or diamond like coating.
29. The superhard composite of claim 1 wherein that the said cutter
shape has a irregular cross section or symmetric cross section such
as an oval, triangular, or a trapezoidal shape.
30. The superhard composite of claim 1 wherein the composite tool
has a typical geometry for cutting and milling inserts.
31. The superhard composite of claim 1 wherein the composite tool
has a typical geometry of inserts used for rolling cutter earth
boring drill bits.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Disclosed herein are elements of superhard polycrystalline
material synthesized in a high-temperature, high-pressure process
and used for wear, cutting, drawing, and other applications. These
elements have specifically placed superhard surfaces at locations
where wear resistance is required. In particular, these elements
are polycrystalline diamond and polycrystalline diamond-like
(collectively called PCD) elements with tailored wear and impact
resistance and methods of manufacturing them.
[0003] 2. Description of the Related Art
[0004] U.S. Pat. No. 4,534,773 discloses a method of producing an
abrasive body of diamond particles in diamond-to-diamond bond with
second phase of Ni and/or Si under condition of a High Temperature,
High Pressure (HPHT) apparatus.
[0005] U.S. Pat. No. 6,861,098 discloses known methods for
fabrication of PDC cutter, inserts and tools. Polycrystalline
diamond and polycrystalline diamond-like elements are known, for
the purposes of this specification, as PCD elements. PCD elements
are formed from carbon based materials with exceptionally short
inter-atomic distances between neighboring atoms.
[0006] One type of polycrystalline diamond-like material is known
as carbonitride (CN) described in U.S. Pat. No. 5,776,615. Another,
more commonly used form of PCD is described in more detail below.
In general, PCD elements are formed from a mix of materials
processed under high-temperature and high-pressure into a
polycrystalline matrix of inter-bonded superhard diamond crystals.
A common trait of PCD elements is the use of catalyzing materials
during their formation, the residue from which, often imposes a
limit upon the maximum useful operating temperature of the element
while in service.
[0007] A well known, manufactured form of PCD element is a
two-layer or multi-layer PCD element where a facing table of
polycrystalline diamond is integrally bonded with a substrate of
less hard material, such as cemented tungsten carbide. The PCD
element may be in the form of a circular or part-circular tablet,
or may be formed into other shapes, suitable for applications such
as friction bearings, valve surfaces, indenters, bearing elements,
earth boring drill bits and the like. PCD elements of this type may
be used in almost any application where a hard abrasive wear and
erosion resistant material is required. The substrate of the PCD
element may be brazed to a carrier, often also of cemented tungsten
carbide. This is a common configuration for PCD's used as cutting
elements, for example in fixed cutter or rolling cutter earth
boring bits when received in a socket of the drill bit, or when
fixed to a post in a machine tool for machining These types of PCD
elements are typically called polycrystalline diamond cutters or
PDC's.
[0008] PCD elements may be formed by sintering diamond powder with
a suitable binder-catalyzing material in a high-pressure,
high-temperature press. One particular method of forming this
polycrystalline diamond is disclosed in U.S. Pat. No. 3,141,746
herein incorporated by reference for all it discloses. In one
common process for manufacturing PCD elements, diamond powder is
applied to the surface of a preformed tungsten carbide substrate
incorporating cobalt. The assembly is then subjected to very high
temperature and pressure in a press. During this process, cobalt
migrates from the substrate into the diamond layer and acts as a
binder-catalyzing material, causing the diamond particles to bond
to one another with diamond-to-diamond bonding, and also causing
the diamond layer to bond to the substrate.
[0009] The completed PCD element has at least one matrix of diamond
crystals bonded to each other with many interstices containing a
binder-catalyzing material metal as described above. The diamond
crystals comprise a first continuous matrix of diamond, and the
interstices form a second continuous matrix of interstices
containing the binder-catalyzing material. In addition, there are
necessarily a relatively few areas where the diamond to diamond
growth has encapsulated some of the binder-catalyzing material.
These "islands" are not part of the continuous interstitial matrix
of binder-catalyzing material.
[0010] In one common form, the diamond element constitutes 85% to
95% by volume and the binder-catalyzing material the other 5% to
15% by volume. Although cobalt is most commonly used as the
binder-catalyzing material, any group VIII element, including
cobalt, nickel, iron, and alloys thereof, may be employed.
[0011] U.S. Pat. No. 7,588,108 describes the fabrication of a high
impact resistant tool that has a sintered body of diamond or
diamond-like particles in a metal matrix bonded to cemented metal
carbide substrate at a non planar interface. The catalyst for
enabling diamond-diamond sintering is provided by the substrate.
Based on known art, the general manufacture of a PDC cutter or
insert or cutting still typically uses a cemented carbide substrate
to provide catalyst to aid in the sintering of the diamond
particles.
[0012] Published U.S Patent Application No. 2005/0044800, describes
the use of a meltable sealant barrier to cleanse the PDC
constituent assembly via vacuum thermal reduction followed by
melting the sealant to provide a hermetic seal for the further HTHP
processing. The sealing of the can used to process the PDC cutter
is required to limit contamination from the catalyst from the
cemented WC substrate to the un-sintered Diamond particle bed
during HTHP processing. HTHP can assemblies to prevent
contamination of the PCD table may also use processes such as EB
welding, as is known for standard production of cutters and
inserts.
[0013] U.S. Pat. No. 5,127,923 describes an abrasive compact that
is subjected to two distinct HTHP operations, the first operation
to produce a PDC cutting element with the use of a solvent catalyst
sintering aid, and the second pressing operation with the use of a
non-solvent catalyst sintering aid.
[0014] U.S. Pat. No. 6,045,440 describes an oriented PDC cutter
where formation chips and debris are funneled away from the cutting
edge via the use of raised top surfaces on the PCD. The redirection
of the debris is achieved by creation of high and low surfaces on
the PCD cutting surface. Although not described in detail, in the
method used to form the protrusion on the PCD, it is assumed that
the surface texture and geometry in this case is limited to its
ability to extrude/form can surfaces that are a negative of the
desired PCD front face extrusions; alternatively post HTHP
processing such as EDM and Laser cutting may be necessary to form
these surfaces on the cutter face. The geometries in this case are
limited to the protruding feature size, pattern and distribution.
The art is, in general, silent about the use of sacrificial
substrates to generate such surfaces on the as formed PCD
table.
BRIEF SUMMARY OF THE INVENTION
[0015] A super hard material composite is described which has an
in-situ formed PCD complex face optimized for aggressive cutting of
formation, low contamination levels in the PCD working surface, and
an integrally bonded substrate that can be optimized for wear and
impact strength. The composite material has a plurality of
hard-phase (Diamond, CBN) particles integrally bonded to plurality
of catalyst-free (W, Mo, V, etc) C particles via temperature and
pressure. Sintering and densification of the composite layer is
aided by catalyst which may be one or more of Co, Ni, and Fe. These
elements may be released from a sacrificial substrate that is
removed by mechanical or chemical methods after composite
manufacture.
[0016] The resultant composite may have features including: a
premixed or mechanically blended diamond/metallic interface to
reduce residual stress, a PCD surface that is the negative of the
substrate, and low residual contamination in the diamond and metal
carbide particles to be moved to the bottom of the post-sintered
PCD substrate. The catalyst flow (sweep) occurs through the diamond
layer, causing a physical action that in essence mechanically bonds
and blends the interface layer and substrate particle bed during
processing. The catalyst sweeps from the substrate toward the
sacrificial substrate, thus pushing the impurities toward the PCD
layer/sacrificial substrate interface and allowing much of the
impurities to be removed while sacrificial substrate is
removed.
[0017] The present invention addresses manufacturing issues with
current PDC cutters and inserts fabrication by including: [0018] A
less stringent requirement for diamond particle purity. [0019] EB
or vacuum brazed sealing of can/container may be used to lower
contamination levels prior to HTHP sintering to inhibit impurity
migration to the PCD surface. [0020] Lapping of wear element face
to remove PCD material that may have a higher impurity
concentration levels (Blemish) due to the catalyst melt flow and
surface interaction with the diamond particles. [0021] The post
HTHP toughness/wear resistance of the sintered substrate that is
used as the catalyst source is controlled by selection of in-situ
sintered substrate grain size. [0022] The infiltration rate and
direction of catalyst is limited by the sintered particle size and
volume % binder in the cemented carbide substrate. [0023] The
texture of the PCD working surface limited to the can geometry.
[0024] Protrusions with hills or valleys on the tool faces for
aggressive cutting are difficult to form with the prior art cell
configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is an illustrative view of a typical drill rig in
operation.
[0026] FIG. 2 is a view of a PCD cutting element typical for those
of the present invention.
[0027] FIG. 3 is a perspective view drill bit which may utilize the
PCD cutting elements of the present invention.
[0028] FIG. 4 is a modified cross section view of a prior art PCD
cutting element in a can ready for HTHP processing.
[0029] FIG. 5 is a perspective view of one embodiment of a PCD
cutting element of the present invention in a suitable can and
ready for HTHP processing.
[0030] FIG. 6A shows one preferred non-planar interface pattern on
a sacrificial substrate used to make a PDC cutting element of the
present invention and FIG. 6B shows a perspective view of the
pattern as it is formed on the finished cutter.
[0031] FIG. 7A shows another preferred non-planar interface pattern
on a sacrificial substrate for a PDC cutting element in the present
invention, and FIG. 7B shows a perspective view of the pattern as
it is formed on the resulting cutter interface.
[0032] FIG. 8A shows still another preferred non-planar interface
pattern on a sacrificial substrate for a PDC cutting element in the
present invention, and FIG. 8B shows a perspective view of the
pattern as it is formed on the resulting cutter interface.
[0033] FIG. 9 is a cross section view a PDC element of the present
invention after HTHP processing and before finishing.
DETAILED DESCRIPTION OF THE INVENTION
[0034] In the following description, it is understood that the
composite described hereafter as formed of polycrystalline diamond,
PCD, or sintered diamond as the material is often referred to in
the industry, but can also be any of the super hard abrasive
materials, including, but not limited to, synthetic or natural
diamond, cubic boron nitride, and related materials.
[0035] Polycrystalline diamond cutters are well known and used as
cutting elements in drilling bits used to form boreholes into the
earth, and are primarily used for, but not limited to, drilling
tools for exploration and production of hydrocarbon minerals from
the earth.
[0036] For illustrative purposes only, a typical drilling operation
is shown in FIG. 1. FIG. 1 shows in schematic form a representation
of a drill string 2 suspended by a derrick 4 for drilling a
borehole 6 into the earth for minerals exploration and recovery,
and in particular petroleum. A bottom-hole assembly (BHA) 8 is
located at the bottom of the borehole 6. Oftentimes, the BHA 8 may
have a downhole drilling motor 9 to rotate an earth boring drill
bit 1.
[0037] As the drill bit 1 is rotated from the surface or by the
downhole motor 9, it drills into the earth allowing the drill
string 2 to advance, forming the borehole 6. For the purpose of
understanding how these systems may be operated, for the type of
drilling system illustrated in FIG. 1, the drill bit 1 may be any
one of numerous types well known to those skilled in the oil and
gas exploration business. This is just one of many types and
configurations of bottom hole assemblies 8, however, and is shown
only for illustration. There are numerous arrangements and
equipment configurations possible for use for drilling boreholes
into the earth, and the present disclosure is not limited to the
particular configurations as described herein.
[0038] As illustrated in FIG. 4, a cross section view of a prior
art cutting element 50 is typically made up of only a
polycrystalline diamond table 55 integrally formed with a substrate
60 of tungsten carbide-cobalt (or other suitable hard metallic
material). There are numerous known variations in configurations,
sizes, shapes and materials for these prior art cutting elements
50.
[0039] A more detailed view of the earth boring drill bit 1 that
may use the cutting elements 10 of the present invention is shown
in FIG. 3. Referring now to FIGS. 2 and 3, a superhard composite
material polycrystalline diamond cutting element 10 of the present
invention may be a preform cutting element 10 for a fixed cutter
rotary drill bit 1 (as shown in FIG. 3). The bit body 14 of the
drill bit may be formed with a plurality of blades 16 extending
generally outwardly away from the central longitudinal axis of
rotation 18 of the drill bit. Spaced apart side-by-side along the
leading face 20 of each blade 16 are a plurality of the PCD cutting
elements 10 of the present invention.
[0040] A typical PCD cutting element 10 may have a body in the form
of a circular tablet having a thin front facing table 22 of diamond
bonded in a high-pressure high-temperature press to a substrate 24
of less hard material such as cemented tungsten carbide or other
metallic material. The cutting element 10 may be preformed as will
be described in detail and then may be bonded on a generally
cylindrical carrier 26 which may also be formed from cemented
tungsten carbide, or it may alternatively be attached directly to
the blade 16. The PCD cutting element 10 has peripheral and end
working surfaces 28, 30 which, as illustrated, are substantially
perpendicular to one another.
[0041] When a cylindrical carrier 26 is utilized, it may be
received within a correspondingly shaped socket or recess in the
blade 16. The carrier 26 may be brazed, shrink fit or press fit
into the socket (not shown) in a drill bit 12. Where brazed, the
braze joint may extend over the carrier 26 and part of the
substrate 24. In operation the fixed cutter drill bit 12 is rotated
and weight is applied. This forces the cutting elements 10 into the
earth being drilled, effecting a cutting and/or drilling
action.
[0042] These cutting elements 10 are typically made in a very high
temperature and high pressure pressing operation (which is well
known in the industry) and then finished machined into the
cylindrical shapes shown.
[0043] The typical process for making these PCD cutting elements 10
typically involves combining mixtures of various sized diamond
crystals, which are mixed together, and processed into the PDC
elements 10 as previously described.
[0044] In various embodiments of the invention, a superhard
composite material comprises a polycrystalline diamond cutter (PDC)
having a flat cutting surface having a polycrystalline diamond
thickness ranging from about 1 to 5 mm or greater--but typically
about 3 mm and a high-temperature, high-pressure (HTHP) in-situ
cemented carbide substrate of about 10 mm thickness that is
integrally formed with the PCD.
[0045] These PDC cutting elements 10 may be made in a manufacturing
process with a preformed can 100 that has at the bottom 112 a
material forming a base substrate 104. An in-situ high-temperature,
high-pressure sacrificial substrate 110 may be placed on top of the
base substrate 104. In a preferred embodiment the base substrate
104 may be domed whereby the thickness at the center is much
greater than the thickness at the sides, as shown in FIG. 9. On top
of the base substrate 104 may be a layer of fine PCD diamond
material 108 which may typically having a range of particle sizes.
This diamond layer 108 will fill the can 100 to a level higher than
the in-situ substrate 106. Because the in-situ substrate 106 may be
domed shaped, (as shown by numeral 114 in FIG. 9) the thickness of
the diamond layer 108 will be less at the center than at the
periphery (as shown). A generally cylindrical sacrificial substrate
110 may be placed on top of the diamond layer 108. Thereafter a lid
112 placed upon the preformed can 100. The can 100 with the above
described mixture is then processed to remove impurities; the can
100 may be welded or otherwise hermetically sealed, and then
subjected to a high pressure, high temperature process as is well
known in the industry.
[0046] What results is a superhard composite material that has a
base substrate 104 and a sacrificial substrate 110 that allows
simultaneous infiltration of the diamond layer 108 from both the
top and the bottom. This process moves the impurities that tend to
be pushed ahead of the liquid front as the sintering process
proceeds toward the center of the sintered diamond material 108,
instead of accumulating at the working surfaces, as is the case in
prior art PDC elements.
[0047] The sacrificial substrate 110 may have various geometrical
surface configurations, as shown in FIGS. 120A, 122A, and 124A.
Although only three geometrical arrangements are shown, it is
understood that a great variety of specific geometrical patters may
be useful, and the present invention is not intended to be limited
only to those shown. When the PDC elements are formed with these
sacrificial substrates, a negative (or mirror image) of the pattern
forms in the PCD layer 108 as the PDC elements is being formed in
the HTHP process.
[0048] In the three specific geometries of the sacrificial
substrates, as represented in perspective views by numeral 120A in
FIG. 6A, 122A in FIG. 7A, and 124A in FIG. 8A, it can be seen that
a negative pattern of the non-planar surface geometry will produced
on the working surface of the finished cutting as shown in the
perspective views of finished cutters 120B, 122B and 124B in FIGS.
6B, 7B, and 8B. These cutting elements 120B, 122B and 124B of the
present invention have the geometrical patterns that were formed by
the patterns on the sacrificial substrate material 110. Even though
the sacrificial substrate 110 is removed (that is why it is called
sacrificial) during processing, a negative of the pattern is left
behind of the finished cutting element, as shown in perspective in
FIGS. 6B, 7B and 8B.
[0049] The end result is a new type of PDC cutting element 10 with
superior physical/mechanical properties as compared to the prior
art. Furthermore, various geometrical patterns may be integrally
formed on the face of the cutting element in the formation process,
providing an integrally formed surface geometry on the `as pressed`
cutter--yielding a PDC cutting element with superior physical and
mechanical properties.
[0050] As part of the manufacturing process, another advantage of
the superhard composite material described above is that it may
further utilize a can 100 with a lid 112 for the HTHP component
assembly with a shrink factor of about 1.10 for minimal OD
grinding.
[0051] The superhard composite material may have a cobalt catalyst
for diamond-diamond particle sintering aid and WC-WC cementation is
supplied by a sacrificial cemented carbide substrate (as will be
described in detail) that may have an average grain size of 20
.mu.m and cobalt of 35 Wt. %, and the finished cutter may be about
1613 mm in diameter.
[0052] Also, the sacrificial substrate 110 in contact with the
diamond particles may form a conic bevel at an outside diameter to
form an in-situ chamfer on the PCD after HTHP processing, and
further, the diamond feed stock may have a mono modal size of about
50 .mu.m. Furthermore, a transition Diamond--WC-Co layer is formed
by using a probing tool that is used to selectively transfer WC-Co
particle into the diamond particle bed to a depth of about 1 mm.
The can 100 and lid 112 may be mechanically sealed and the can 100
is exposed to a HTHP process to enable composite densification
aided via a catalyst infiltration from the cemented carbide
substrate into the diamond and WC-Coparticle bed. The cemented
carbide substrate is a sacrificial substrate, and the HTHP
processing may require at least 40 k bar pressures and a
temperature of at least 1000.degree. C.
[0053] The sweep or movement of the catalyst during HTHP processing
may occur from the top of the PCD surface to the bottom of the
in-situ formed substrate and after HTHP processing, the super hard
composite is finished by removal of the can 100 and substrate 110
and OD grinding.
[0054] The sacrificial substrate 110 may be separately formed of a
metal carbide selected from the group including a tungsten carbide,
titanium carbide, tantalum carbide, and mixtures thereof, and the
sacrificial substrate 110 may be formed of a carbide from the group
of IVB, VB, or VIB metals which is pressed and sintered in the
presence of a binder of cobalt, nickel, iron, and alloys thereof,
and may further have: [0055] an average carbide particle size
greater than >3 .mu.m, [0056] a weight % of binder material
>3%, [0057] a binder of Co, Ni, or Fe with at least 5 wt % Co in
the sacrificial binder phase,
[0058] The WC may be replaced with MC comprising M=V, Mo, Ti, Ta)
and mixes thereof with a WC content of at least 5 wt %, and also
the sacrificial binder substrate that has M, C, Co (Fe, Ni) a
eutectic composition forming 100% melt at the eutectic temperature;
W-C--Co or W-C--Ni eutectic temperate is about 1270 degrees C.
There may also be a surface texture of the sacrificial substrate
110 in contact with the diamond particle which has a surface
texture on the substrate is the negative of the desired roughness
on the cutting element face, and, the texture is formed by pressing
the grade mix or post sintered operations including laser, EDM or
other methods for providing the texture.
[0059] The above superhard composite material may also have a
texture supporting chip breaker geometries used for milling and
turning inserts to aid with chipping of formation, and may have
diamond particles with a multi-modal size distribution for optimal
packing with a size range of 1 nm to 100 .mu.m, and, the diamond
particles have a carbon phase additive >5 wt % that is amorphous
or nano structure fullerenes.
[0060] In addition, the superhard composite may have diamond
particles which are replaced with CBN particles, and may further
have a mixture of Diamond and CBN particles with at least 0.5 wt %
diamond particles with an interface, with the interface probing
depth 100% of the PCD layer with a low WC concentration near a
sacrificial substrate 110 and a high concentration near the
WC-diamond interface.
[0061] The WC content in diamond particle bed ranges at the
preformed interface ranges from 1 wt % to 80 wt % and the Carbide
particles are formed of a metal carbide selected from the group
consisting of tungsten carbide, titanium carbide, tantalum carbide,
and mixtures thereof from the group of IVB, VB, or VIB metals, and
comprising a multi modal particle size distribution for optimal
packing with a size range of 1 nm to 100 .mu.m., at least 5 wt % of
the particles may be >50 .mu.m to ensure adequate erosion
resistance of the HTHP in-situ formed substrate.
[0062] The diamond particles, interface and WC particle bed may be
preforms manufactured using a fugitive binder like PEG, mineral oil
and methyl cellulose to limit segregation during transfer to the
can 100, where a moldable diamond mix is pressed in the can 100 to
conform to the sacrificial substrate 110 texture, an interface is
formed by using a probing tool to transfer a given amount of WC mix
into the diamond mix, a WC mix is pressed into the can 100 above
the interface, and, the fugitive binder is removed in the presence
of hydrogen.
[0063] The superhard composite may also have a sink for a catalyst
abridging the WC bed to reduce catalyst content in the densified
PCD/substrate where the sink comprises loose Zirconia ceramic
particles and the like, that have greater resistance to HTHP
sintering than WC particles in the presence of the catalyst, and
wherein the sink is removed after HTHP processing via a EDM, laser
or abrasive cutting and furthermore, substrate removal may be by a
mechanical dry/wet abrasives grinding or chemical leaching or a
combination of both methods.
[0064] The PCD face may be coated with a nano coating diamond or
diamond like coating, and the cutter shape may have an irregular
cross section, or an asymmetric cross section such as an oval,
triangular, or a trapezoidal shape.
[0065] Furthermore, described herein is a superhard composite
material having a polycrystalline diamond material comprising a
generally flat cutting surface of a polycrystalline diamond
material and having a thickness of about 3 mm further comprising a
high-temperature, high-pressure (HTHP) in-situ cemented carbide
substrate integrally bonded to the PCD.
[0066] The material may also comprise a can 100 and a lid 112 for
the HTHP component assembly with a shrink factor of about 1.10 for
minimal OD grinding, and have a cobalt catalyst for Diamond-Diamond
particle sintering and WC-WC cementation that is supplied by a
sacrificial cemented carbide substrate with an average grain size
of 20 .mu.m and cobalt of 35 wt. %.
[0067] The finished cutter described above may be about 1613 mm in
diameter, and have a the sacrificial substrate 110 in contact with
the diamond particle forms a conic bevel at an outside diameter to
form an in-situ chamfer on the PCD after HTHP processing.
[0068] In addition, the diamond feed stock is a mono modal size of
about 50 .mu.m and the WC particle size in contact with the diamond
particle may be a mono modal size of about 50 .mu.m.
[0069] The superhard composite material may have a transition
Diamond--WC layer is formed by using a probing tool that is used to
selectively transfer WC particle into the diamond particle bed to a
depth of about 1 mm, and be processed in a can 100 and lid 112
which are mechanically sealed.
[0070] During processing, the can 100 may be exposed to a HTHP
process to enable composite densification aided via a catalyst
infiltration from the cemented carbide substrate into the diamond
and WC particle bed, so that the cemented carbide substrate acts as
a sacrificial substrate 110, and the HTHP processing requires at
least 40 kbar pressures and a temperature of at least 1000.degree.
C.
[0071] The sweep or movement of the catalyst during HTHP processing
may flow from the top of the PCD surface to the bottom of the
insitu formed substrate.
[0072] The sacrificial substrate 110 may be formed of a metal
carbide selected from the group consisting of a tungsten carbide,
titanium carbide, tantalum carbide, and mixtures thereof or it may
be formed of a carbide from the group of IVB, VB, or VIB metals
which is pressed and sintered in the presence of a binder of
cobalt, nickel, iron, and alloys thereof, and may further have:
[0073] an average carbide particle size greater than >3 .mu.m,
[0074] a weight of binder >3%, [0075] the binder containing Co,
Ni, or Fe with at least 5 wt % Co in the sacrificial binder phase.
The WC may be replaced with MC comprising M=V, Mo, Ti, Ta (and
mixes thereof) with a WC content of at least 5 wt %.
[0076] The sacrificial binder substrate may also form a M, C, Co
(Fe, Ni), a eutectic composition forming 100% melt at the eutectic
temperature; the W, C, Co--Ni eutectic temperate is about 1270
degrees C.
[0077] The surface texture of the sacrificial substrate 110 in
contact with the diamond particle may form a surface texture on the
substrate is the negative of the desired roughness on the cutting
element face, and the texture may be formed by pressing the grade
mix or post sintered operations including laser, EDM or other
methods for providing the texture.
[0078] The texture may have incorporated within it chip breaker
geometries used for milling and turning inserts to aid with
chipping of formation, and the diamond particles may have a
multi-modal size distribution for optimal packing with a size range
of 1 nm to 100 .mu.m, and the diamond particles have a carbon phase
additive >5 wt % that is amorphous or nano structure
fullerenes.
[0079] The diamond particles may be replaced with CBN particles or
may be a mixture of Diamond and CBN particles comprising at least
0.5 wt % diamond particles. The interface probing depth may be 100%
of the PCD layer with a low WC concentration near the sacrificial
substrate 110 and with a high concentration near the WC-diamond
interface.
[0080] The WC content in diamond particle bed ranges at the
preformed interface ranges from 1 wt % to 80 wt %, and the Carbide
particles may bee formed of a metal carbide selected from the group
consisting of tungsten carbide, titanium carbide, tantalum carbide,
and mixtures thereof from the group of IVB, VB, or VIB metals, and
further have a multi modal particle size distribution for optimal
packing with a size range of 1 nm to 100 .mu.m. At least 5 wt % of
the particles are >50 .mu.m to ensure adequate erosion
resistance of the HTHP in-situ formed substrate.
[0081] The superhard composite may have the diamond particles,
interface and WC particle bed as made as performs, manufactured
using a fugitive binder like PEG, mineral oil and methyl cellulose
to limit segregation during transfer to the can, so that a moldable
diamond mix may be pressed in the can to conform to the sacrificial
substrate 110 texture, and an interface is formed by using a
probing tool to transfer a given amount of WC mix into the diamond
mix and a WC mix is pressed into the can above the interface, and
then the fugitive binder is removed in the presence of
hydrogen.
[0082] The superhard composite may also have a sink for a catalyst
abridging the WC bed to reduce catalyst content in the densified
PCD/substrate such that the sink has loose Zirconia ceramic
particles and/or the like, that have greater resistance to HTHP
sintering than WC particles in the presence of the catalyst, and
the sink is removed after HTHP processing via a EDM, laser or
abrasive cutting.
[0083] The substrate may be removed from the superhard composite by
a mechanical dry/wet abrasives grinding or chemical leaching or a
combination of both methods, and furthermore, the PCD face of the
composite may be coated with a nano coating diamond or diamond like
coating. The cutter shapes may include those with an irregular
cross section or symmetric cross section, such as an oval,
triangular, or a trapezoidal shape.
[0084] Finally, the superhard composite may also form a composite
tool with a typical geometry for cutting and milling inserts, or,
it may have a typical geometry of inserts used for rolling cutter
earth boring drill bits.
[0085] Whereas the present invention has been described in
particular relation to the drawings attached hereto, it should be
understood that other and further modifications apart from those
shown or suggested herein, may be made within the scope and spirit
of the present invention.
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